This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Yes, you can, but not recommended. If u decide to go this way you may use POJO classes as DAO objects and build facade session beans to access them. You may also build BMP entity beans or eve use a persistent framework as Hibernate to get to the DB. regards.